Implement full JBOD monitor frontend from design JSX

- Dark/light theme toggle, grid/table view toggle
- Expanded DriveHealthSummary with wwn, firmware, capacity, SMART
  counters, and computed health_status field
- Drive detail modal with identity, WWN, ZFS membership, SMART health
- 30s auto-refresh

routers/overview.py

@@ -68,15 +68,33 @@ async def get_overview():
                 if sd.get("uncorrectable_errors") and sd["uncorrectable_errors"] > 0:
                     warnings += 1
 
+                # Compute health_status for frontend
+                realloc = sd.get("reallocated_sectors") or 0
+                pending = sd.get("pending_sectors") or 0
+                unc = sd.get("uncorrectable_errors") or 0
+                if healthy is False:
+                    health_status = "error"
+                elif realloc > 0 or pending > 0 or unc > 0 or (healthy is None and sd.get("smart_supported", True)):
+                    health_status = "warning"
+                else:
+                    health_status = "healthy"
+
                 drive_summary = DriveHealthSummary(
                     device=sd["device"],
                     model=sd.get("model"),
                     serial=sd.get("serial"),
+                    wwn=sd.get("wwn"),
+                    firmware=sd.get("firmware"),
+                    capacity_bytes=sd.get("capacity_bytes"),
                     smart_healthy=healthy,
                     smart_supported=sd.get("smart_supported", True),
                     temperature_c=sd.get("temperature_c"),
                     power_on_hours=sd.get("power_on_hours"),
+                    reallocated_sectors=sd.get("reallocated_sectors"),
+                    pending_sectors=sd.get("pending_sectors"),
+                    uncorrectable_errors=sd.get("uncorrectable_errors"),
                     zfs_pool=pool_map.get(sd["device"]),
+                    health_status=health_status,
                 )
             elif s["populated"]:
                 total_drives += 1